National Centre for Coasts and Climate, School of BioSciences, The University of Melbourne, Melbourne, Victoria, 3010, Australia.
U.S. Geological Survey, Louisiana Cooperative Fish and Wildlife Research Unit, School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, 70803, USA.
Ecol Appl. 2021 Sep;31(6):e02382. doi: 10.1002/eap.2382. Epub 2021 Jun 29.
One of the paramount goals of oyster reef living shorelines is to achieve sustained and adaptive coastal protection, which requires meeting ecological (i.e., develop a self-sustaining oyster population) and engineering (i.e., provide coastal defense) targets. In a large-scale comparison along the Atlantic and Gulf coasts of the United States, the efficacy of various designs of oyster reef living shorelines at providing wave attenuation was evaluated accounting for the ecological limitations of oysters with regard to inundation duration. A critical threshold for intertidal oyster reef establishment is 50% inundation duration. Living shorelines that spent less than one-half of the time (<50%) inundated were not considered suitable habitat for oysters, however, were effective at wave attenuation (68% reduction in wave height). Reefs that experienced >50% inundation were considered suitable habitat for oysters, but wave attenuation was similar to controls (no reef; ~5% reduction in wave height). Many of the oyster reef living shoreline approaches therefore failed to optimize the ecological and engineering goals. In both inundation regimes, wave transmission decreased with an increasing freeboard (difference between reef crest elevation and water level), supporting its importance in the wave attenuation capacity of oyster reef living shorelines. However, given that the reef crest elevation (and thus freeboard) should be determined by the inundation duration requirements of oysters, research needs to be refocused on understanding the implications of other reef parameters (e.g., width) for optimizing wave attenuation. A broader understanding of the reef characteristics and seascape contexts that result in effective coastal defense by oyster reefs is needed to inform appropriate design and implementation of oyster-based living shorelines globally.
牡蛎礁生态护岸的主要目标之一是实现可持续和适应性的海岸保护，这需要满足生态（即发展自我维持的牡蛎种群）和工程（即提供海岸防御）目标。在美国大西洋和墨西哥湾沿岸的大规模比较中，评估了各种牡蛎礁生态护岸设计在提供波浪衰减方面的效果，同时考虑了牡蛎在淹没持续时间方面的生态限制。潮间带牡蛎礁建立的一个关键阈值是淹没持续时间的 50%。淹没时间少于一半（<50%）的生态护岸不被认为是牡蛎的适宜栖息地，但在波浪衰减方面非常有效（波高降低 68%）。经历>50%淹没的礁被认为是牡蛎的适宜栖息地，但波浪衰减与对照（无礁；波高降低约 5%）相似。因此，许多牡蛎礁生态护岸方法未能优化生态和工程目标。在这两种淹没状态下，随着自由甲板（礁顶高程与水位之间的差异）的增加，波浪传输减少，这支持了它在牡蛎礁生态护岸波浪衰减能力中的重要性。然而，鉴于礁顶高程（因此自由甲板）应根据牡蛎的淹没持续时间要求来确定，因此需要重新关注理解其他礁参数（例如宽度）对优化波浪衰减的影响。需要更广泛地了解导致牡蛎礁有效防御海岸的礁特征和海洋景观背景，以便为全球基于牡蛎的生态护岸的设计和实施提供信息。
